[PSUBS-MAILIST] R300 Dive report - Canyon Lake, Tx

Tue Sep 1 17:40:49 EDT 2015

 I took the R300 out this weekend.  This was the first time to have it back
in water since the 2013 Psub convention in Islamorada.  The objective of
the dive was to evaluate some fairly significant modifications.

To improve low speed maneuverability and reduce noise, I junked the jet
pump and ailerons and went to four fixed MK 101 thrusters. I also junked
the VBT and just add ballast to get neutral. Also I added a Garmin AIRMAR
DST800 Smart Sensor to measure altitude, speed and water temperature.  It
worked great.  Installed a new LED 5k light, upgraded to a new HMI, and
changed the foot and joystick controls.  I also rewired the main battery
bank for 36VDC rather than 120VDC and installed four MK 101 motor
controllers.  I modified the aft horizontal MK-101s by adding Kort nozzles
and used air to pressure compensate.  I used the same pressure reducing
regulator Hugh Fulton posted about awhile back that he is using on the QSub.
  The changes decreased the weight of boat by 200 lbs while the
displacement remained the same.

My son, wife, a diving friend and I took the boat to Canyon Lake in Texas
this Sunday.  Visibility was less than 5 ft so could not see much.  My main
interest at this point was just to get into water.  After launching the
boat, I did some testing to get the base line ballast both mid-ship and in
the stern correct so that I could get neutral and trim after flooding the
MBT.  After establishing the fixed ballast, I took the boat out to test how
the horizontal thrusters work for surface maneuvering.   I was very happy
with way the horizontal thrusters performed. Surface maneuverability was
excellent and these motors are supper quite.  I did find that you could
cavitate the props on the surface if you hit it with too much power. As
before the changes, when you get up to about 4 knots, the bow wave obscures
the pilots vision.   Breaking is much improved and it is now possible to
rotate on the surface or in the water column.

I then took the boat out for the first submerged maneuvering.  The vertical
thrusters were very effective for depth control, pitch and roll control.  I
found that it was much easier to get to specific depth and hold this depth
using the vertical thrusters than the old way I did it with the VBT.  They
worked great.  While removing the VBT simplified dive operations, it did
result in loss of freeboard of about 1 inch.  This is a downside of
removing the VBT as the freeboard was already quite low.  I just have to be
careful when opening the hatch.  I opened and closed that hatch throughout
the day and only took splash one time when a boat came by I did not see.

The new Garmin AIRMAR DST800 Smart Sensor worked great. With visibility
less than 5 ft, being able to know the altitude was very helpful on dives.
As usual, it got darker as you descend but knowing when the bottom was
coming up was nice.

On the negative side, during the last dive of the day, the vertical
thrusters failed while my son was on bottom in about 27 ft of water.  He
had to surface using the MBT. Why these thrusters failed is a mystery.  It
was at the end of the day and I had pushed the batteries pretty hard all
day along but we still had plenty of battery voltage.   My sons second
attempt to surface was to put some air in the forward MBT to lift the nose
and then use the aft horizontal thrusters to power to the surface.  This
failed as aft horizontal thrusters were not responsive.  After surfacing
with the MBT, we discovered that tree limb about 1.5” diameter had lodged
in the starboard horizontal thruster between the prop and the Kort
nozzle.  This
explains why we lost horizontal thrust but not vertical.  After getting the
boat back on the trailer, I tested the vertical thrusters.  They would
barely turn even when giving them full power.  My first guess was that the
air pressure compensation system failed and the thrusters were full of
water.  When I got the boat back to my workshop, I disassembled both
vertical thrusters and discovered they were dry. After recharging the boat,
I tried the vertical thrusters again and got the same slow speed operation.
After turning them off and on for about five minutes, the starboard
vertical thruster stared working correctly.  I kept switching the port
vertical thruster off and on and all of a sudden, it began working
correctly.  When I had the motors apart, I put a multimeter on the wires
going to the brushes and found it showing 35VDC.  At this point the control
signal to these motors was 2.5V so voltage to the motors should have been
zero.   My guess is that the MK motor controller is acting up.  But it is
strange that both the vertical controllers would fail.  Also, if it were
bad motor controllers, then why did they both start working again.  This is
still a head stumper for me.

Also towards the end of the day, the OTS underwater communication stared
acting up.  Base and standby diver using an OTS Guardian full face mask
could hear underwater transmissions from me but I could not receive either
from the diver or from the base.  The underwater commns had been working
great for the previous 7 hours.   I was also having trouble about this time
with the VHF radio that Alec gave me.  Again I could not receive.  When I
get a chance I am going to see if the connection to the antenna got
disconnected.

One of the nice new features of the new HMI besides being larger and having
a higher resolution, was it has built in data logging.  So after the dive
it was very nice to be able to download into Excel about 50 variables
logged at a one minute interval. I was able to plot these and get a
detailed picture of how all the ship systems were working during the day.

If anyone has any thoughts on why the vertical MK 101 thruster motors
failed, or have had any negative experience with the MK101 motor
controllers, I would love to hear them.  When they are working, they are
great.

All in all, I was very happy with the changes but have a few kinks to work
out before I take her out again.  Now if I could just find some clear water
to dive in, I would be a happy camper!

Cliff
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